The semiconductor industry has progressed into nanometer technology process nodes in pursuit of higher device density, higher performance, and lower costs. As this progression takes place, challenges from both fabrication and design issues have resulted in the development of three-dimensional designs, such as fin-like field effect transistor (FinFET) devices. The use of FinFET devices has been gaining popularity in the semiconductor industry. FinFET devices offer several advantages over traditional Metal-Oxide Semiconductor Field Effect Transistor (MOSFET) devices (also referred to as planar devices). These advantages may include better chip area efficiency, improved carrier mobility and fabrication processing that is compatible with the fabrication processing of planar devices. Thus, it may be desirable to design an integrated circuit (IC) chip using FinFET devices for a portion of, or the entire IC chip.
A typical FinFET device is fabricated with a thin fin-like structure called a “fin”, extending from a substrate, and a gate provided over (e.g., wrapping around) the fin. The fin structure is made of semiconductor material, typically silicon, and if used as a transistor, has a current channel formed inside. When the FinFET device is used as a transistor, the gate is used to control the current in the channel.
A diode can be built on a FinFET structure using silicon-on-insulator (SOI) technology in a fashion generally identical to those built in today's planar SOI technologies or bulk CMOS technologies. Compared to the traditional planar semiconductor diodes, however, the diodes constructed by using the FinFET structure have a shortcoming of reduced efficiency due to the degradation caused by the fin structures. The presence of plural fin structures in the FinFET diodes reduces the active area for producing injection current, and thereby decreases efficiency of the diodes, defined by injection current generated per a unit cell area.
Therefore, there is a need to provide a FinFET diode and a method to manufacture the same that has a higher efficiency than the conventional FinFET diodes.